Configuration and inheritance chains in PHP - php

Question

I have a few standard classes:
abstract class Parent {}
class Child1 extends Parent {}
class Child2 extends Parent {}
The Parent class contains logic common to both child classes, but each child class has its own additional logic.
For each of my clients, this logic can be configurable. So for any particular client, I may have:
abstract class ClientParent {}
class ClientChild1 extends ClientParent {}
class ClientChild2 extends ClientParent {}
The problem I'm having is how to get the logic from the standard classes into these ones. The first approach would be something like this:
abstract class ClientParent extends Parent {}
Okay, now I have the standard parent logic in all my client-specific classes. Great. But the child classes are already extending ClientParent, so we can't do the same thing for them. My "solution" is then to do this:
abstract class Parent {}
class Child1 extends ClientParent {}
class Child2 extends ClientParent {}
abstract class ClientParent extends Parent {}
class ClientChild1 extends Child1 {}
class ClientChild2 extends Child2 {}
There; now all the appropriate logic is passed down and everybody's happy. Except that now my standard classes are coupled to a particular client. As I have many clients, this is obviously no good.
What's my out here? Is there a way to address this through inheritance alone, or should I look into more complex configuration injection strategies?
Edit:
I'm using PHP 5.3, so I am unable to use traits to solve this problem.

Answer 1

PHP does not support multiple inheritance which is what I think you are trying to approximate here. It does however support (as of 5.4) traits, which in many cases can provide you with comparable functionality.
trait ParentTrait {
public function someUsefulMethod(){/*...*/};
public function someOtherUsefulMethod(){/*...*/};
}
abstract class ClientParent(){}
class ClientChild1 extends ClientParent {
use ParentTrait;
}
$clientChild1 = new ClientChild1();
$clientChild1->someUsefulMethod();
Another option would be to use composition instead, possibly for your problem employing the Strategy pattern would work.
class SuperWidget extends Widget{
private $dataStrategy;
public function __construct(DataStrategy $strategy){
$this->dataStrategy = $strategy;
}
// do this if you need to expose the functionality.
public function getData(){
return $this->dataStrategy->getData();
}
// or if you are just using it in your class
public function renderWidget($option){
$data = $this->dataStrategy->getData($option);
// use the data to render the widget;
return $renderedWidget;
}
}
$dataStrategy = JsonDataStrategy("http://data.source.url/jsonService.php");
$widget = new SuperWidget($dataStrategy);